#include <stdio.h>
 
int is_leap_year(int year) {
    if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
        return 1; // 是闰年
    } else {
        return 0; // 不是闰年
    }
}
 
int main() {
    int year;
    printf("Enter a year: ");
    scanf("%d", &year);
 
    if (is_leap_year(year)) {
        printf("%d is a leap year.\n", year);
    } else {
        printf("%d is not a leap year.\n", year);
    }
 
    return 0;
}